Self regulated heat transfer system



Nov. 9, 1937. s p, MlLLER 2,098,462

SELF REGULATED HEAT TRANSFER SYSTEM Filed May 15, 1936 2 sheets-sheet 1n L n 4I'I--N Il Il k Il II n `v-"Vmr Y :l E: `-J1 .-11 5 11 -f` JZ J2 iJe lili! f i an -I Z ge s Nov. 9, 1937,4

s. P. MILLER 2,098,462 SELFl REGULATED HEAT TRANSFER SYSTEM Filed May15, 1936 2 sheets-sheet 2 Patented Nov. 9, i937 UNT TTES saar enumerannaar TRANSFER srs'rnrr Samurai 1P; Miller, Chicago, Ill.

Appiication May 15, 1936, Serial No. 79,842

En @amada January 27, 1936 29 Claims.

'Ny invention relates to improvements in self regulated heat transfersystems and has for a particular object the provision of a heat transfersystem in which the pressure or degree of 5 vacuum through the entiresystem may be maintained at a substantially uniform and predeterminedpoint without any human intervention.

This application is a continuation in part of my application for patenton Self regulated heat transfer systems, Serial No. 699,557, first ledin the United States Patent Oilce on November'Zi, 1933, and renewed onApril 425, 1936, and my application for patent on Heat transfer systems,Serial No. 1,091, flied in the United States Patent l5 Omce on January10, 1935.

Another object is to provide such a system.

at a very small cost and one which may be employed with known heatAtransfer systems without occasioning expensive changes.

Another object of my invention is to provide a heat transfer system inwhich the pressure in the secondary steam line may be maintained at aVery low point, even below atmosphere, and yet provide sufficient heatfor the transfer system.

The expansion of steam as used in the ordiynary steam heating system oftoday causes a loss in the amount of steam necessary for the work, dueto the fact that being controlled from the near end only, expansion ofsteam through the entire header and riser system results, which accountsfor the greatest amount of the so-called friction in the lines, sinceexpansion causes friction, and expanding steam also creates anoncondensible gas which is lighter than expanded steam andwhichtherefore 'goes to the top of radiators. Iljhe dew formed of expandedsteam goes to the bottom of the radiators, keeps the thermostatic trapsshut on due to the heat content, and therefore the gases are notremovable by the ordinary vacuum pump. Expansion causes absorption fromthe steam to the water, ordinarily calledrefrigeration, thereforerequiring more steam to do the same work than when there is lessexpansion of the steam. Expansion causes large amounts of water'to becondensed in headers and risers, due to this expansion andrefrigeration, and this water will not be re-evaporated. In other words,if the steam is kept from expanding in headers and risers, no steam willturn to water, and if it did, due to radiation, it would re-evaporateinto steam.

In my invention I stop the larger parts of these losses due to expansionby connecting the headers and risers at the near end and the far endwith the control valve diaphragm through a control or biasing meanswhereby headers, risers, and far end return lines, either one affectingthe reducing valve or control means, cause more or less steam to bedelivered to the headers because 5 one ounce of variation of the controlor biasing means would affect the reducing valve diaphragm to the extentof eight ounces, due to the diameter of the reducing Valve diaphragmwhich is not less than eight inches. Three Aounces less l0 pressure onthe diaphragm than the valve is set for would open the valve wide open.Therefore I would have the. risers and headers all full of steam at notless than one ounce difference from end to end to maintain theequilibrium l5 of the valvesetting. Therefore the entire expansion ofthe steam in the headers and risers would not exceed one ounce whichwould not set up much absorption and refrigeration; also it would notdrop much or any water in the 20 headers and risers. This also stops theboiling of the water in the return lines because the Water does notlabsorb heat from the steam in the quantities it would under expansion ofthe steam, and the returns will operate so near the pressure in theheaders and risers the difference in the boiling points at the diierentpressures between the two would not permit the same.

Regulating Valves are very old in the heating art, and it is well knownthat they are employed 30 and interposed between a primary steampressure line and a secondary steam pressure line. The primary steampressure line ordinarily conducts steam from a boiler or other source'ofsteam at a considerably higher pressure than is desired to be introducedinto the secondary steam pressure -line; the regulating valves justmentioned are designed to effect such a reduction of pressure andmaintain in the secondary line a substantially uniform and predeterminedpressure regardless of the pressure in the primary line. Theseregulating Valves are ordinarily provided with a manually operable setwheel by which the operator or engineer sets the valve to maintain adesired pressure in the secondary line. It has been found, however, thatregardless of the skill and knowledge employed in making regulatingvalves and heating systems, pressures at various points throughout ltheheat transfer system vary a considerable degree. This variation is mostnoticeable, of course, between 'a point close to the beginning of thesecondary steam line and the far end of the secondary and risers wherecondensed steam is collected for reevaporation.' A cause of thevariation in pressure and temperature is the friction offered by thesteam line to the passage of steam therethrough. As before stated one ofmy objects is to provide a heat transfer system in which variations inpressure and temperature or degree of vacuum throughout the system aresubstantially eliminated, and in which the pressure or degree of vacuummay be automatically maintained at a predetermined point.

Some heat transfer systems are commonly known as vacuum systems and arein wide use. Some of these systems employ exhaust steam from a powergenerating engine to supply heating systems or other heat transfersystems. In the type of system just mentioned the primary steam linefrom the boiler or other source of steam is provided with a by-pass, oneside of which supplies steam to a power generating engine under boilerpressure, and the other side of which supplies steam under the samepressure to a reducing or regulating valve, which in turn communicateswith the main secondary steam line. The exhaust steam from the powergenerating engine is received in a tank also communicating. with themain secondary steam line. A vacuum is preferably maintained in thesecondary steam line and exhaust st eam receiving tank in order toincrease the eiiiciency of the power generating engine and the .heattransfer system. With my system steam may be delivered from the boilerto the heat transfer system at f as much as ten inches of vacuunrifdesired; the

vacuum may be maintained at a constant degree by the automatic openingand closing of the regulating or reducing valve interposed between theprimary from the boiler and the main secondary steam line. It can beseen that such a result is highly desirable and increases the efflciencyof the power generating engine and heating system as well.

My invention may be understood clearly from rthe following specicationand drawings, in

which:

Fig. 1 is a 'somewhat diagrammatic layout of a heat transfer systememploying my regulating means;

Fig. 2 is a detail view in section of the pilot valve of a conventionaltype regulating valve with some of my connections attached thereto;

Fig. 3 is a sectional View of a conventional type of check valveemployed for preventing the water, pressure, or vacuum in thecondensation chamber from affecting the pressure or vacuum of the heattransfer system;

Fig. 4 is a diagrammatic view of a modified steam heating systemembodying the princip1e of my invention; and

` Fig. 5 is a vertical sectional view of the control and reducing valveof said system shown in detail.

Referring particularly to Figs. 1, 2, and 3, a conventional type boiler5 may be employed to deliver steam to a primary steam line 6 which isconnected to the high pressure side of a regulating valve generallyindicated at 1. A secondary steam line 8 is connected to the lowpressure side of regulating valve 1. Secondary line 8 isconnected at itsfar end with a pipe 9 which empties into a condensation chamber I0.Branch steam .lines I I conduct steam from secondary line 8 to amultiplicity of steam consuming units or radiators I2, and the ends ofbranch pipes II arereceived by a condensate manifold pipe I3 whichempties into a pipe I4. The pipe I4 empties into condensation chamberI0, and a check valve I5 is arranged in line I4 for the purpose abovementioned. Various return pipes I5 conduct condensed and used steam fromthe heat consuming units I2 and empty into return manifold I1 whichempties into a return line I8 having its lower end communicating withcondensation chamber I9. A similar check valve 2li is arranged in returnline I8.

The particular type of regulating valve illustrated is typical of theconstruction employed in regulating valves although various types employsome modification in structure. Referring now to Fig. 2 the regulatingvalve 1 is under the control of a pilot Valve 2i whose stem 22 extendsupwardly through a guide web 23 and into a diaphragm chamber 24. Theupper end of the stem 22 abuts against a diaphragm 25. The lower end ofthe stem 22 extends into a spring housing chamber 26 and is encircled bya coil spring 21. A collar 28 is pinned to the stem, and the compressionspring 21 presses upwardly on collar 28 to urge the valve 2| to a closedposition on valve seat 29. A spring urged disk 30 seats on the upperface of diaphragm 25 and is provided with a stem guide 3| for thesliding reception of a screw stem 32. A compression spring 33 isarranged on screw stem 32 and seats in a groove 34 on the upper face ofdisk 30. The upper end of spring 33 seats against a follower 35 whichcarries a longitudinally threaded bore 36 int-o which stem 32 is turned.A pair of guide lugs 31 on follower 35 seat in appropriate grooves ofhousing 38 and prevent the rotation of said follower.

A steam line 39 extends from high pressure side of the regulating valve1 to the valve chamber 40 of pilot valve 2|'. The opening of the pilotvalve 2| permits steam from the high pressure side to pass into outletchamber 4I and thence into steam line 42. The steam line 42 communicateswith the lower end of a cylinder 43 shown in Fig. 1 and drives piston 44upwardly. A main valve stem 45 is connected to piston 44 at one end anda main valve 45 at its opposite end. Valve 46 in closed position seatson main valve seat 41 and prevents the passage of steam from highpressure primary to the lower pres- -valve 2I to be unseated in order toadmit steam to outlet chamber 4I for action .upon piston 44.

The novel part of my invention and the part which enables theaccomplishment of startling results is the following described system ofintercommunicating by-passes. A pipe 49 of relatively small dimensionsis arranged to conduct steam from secondary pipe 8 to a T fitting 50. Apipe 5I is connected with one end of T fittingl 50 and has its oppositeend communicating with diaphragm chamber 24 heretofore described. A pipe52 is connected to the other end of T fitting 5Il and has its oppositeend communicating with a T fitting 53. A pipe 54 extends between pipe 52and a T fitting 55 arranged in pipe I8. A pipe 56 is connected at oneend with T fitting 53 and at its opposite endwith a T fitting 51 whichis arranged in pipe 9.-

il'he operation of my system as described above is as follows: 'I'hehand wheel 48 is turned so as to depress diaphragm 25 and valve 2l alsumcient distance to permit a desiredy pressure in secondary steam line8. Steam from the primary 6 passes through pipe 39, pilot valve chamber40, outlet chamber 4I, pipe 52, and pushes upwardly on piston 44 incylinder 53. Main valve 551s thus opened and steam passes into thesecondary and likewise into cylinder 53. The pressure on.

the upper face of piston de tends to force it downwardly and thusdecrease the opening of main valve 46. The steam passing into secondary5 passes through the various pipes l l, steam consuming units l2,manifold i3, far'end 9, return manifold I'l, return pipe i8, pipe i4,and thence into condensation collecting chambers it! and i9. However,steam also passes from secondary 8 to pipe 49 and to T fitting 5i).Since the tension of coil spring 33 opposes the raising of diaphragm 25by the steam pressure passing through T tting and pipe 5l to `diaphragmchamber 25, the steam follows the line of least resistance and passesthrough pipe 52 to T fitting 53. As before stated T fitting 53 by-passessteam from line 52 to pipe I8, which is connected`with return manifoldil which collects water of condensation from the various steam consumingunits, and to pipe 55 which communicates with T tting 5l arranged inpipe 5; pipe 9 is the far end of secondary line 8. When Steam throughpipe 52 reaches T fitting 55 it will again follow the line of leastresistance, or enter the pipe having the smallest pressure therein, andwill continue to do so until the pressures in pipes yI8 and 9 areequalized. As soon as the pressures in pipes i3 and 5 are suihcientlygreat, the pressure in pipe 52 supplied through pipe 49 will be exertedthrough pipe 5| and cause the passage of steam into diaphragm chamber2d, the steam pressure on diaphragm 25 will cause the raising ofdiaphragm 25 when the pressure becomes suciently great, and when thisoccur.;` compression spring 2l will urge valve stem 22 upwardly and urgepilot valve 2i toward its seat 29. It should be noted carefully,however, that no closing action on pilot valve 2| will occur until anequalization of pressure and a building up of sumcient pressure havebeen accomplished as above set out.

Under certain circumstances, particularly moderately sized systems, itis Apossible lto omit pipe 56, and under other circumstances to omitpipe 5d. Under these conditions I have found that satisfactory operationof the control valve will result with pipe 52 connected either ,to pipe9 or I3 as the particular condition may warrant.

A check valve 58 prevents water of condensation, pressure, or vacuum inthe condensation 'chamber from affecting the heating system throughreturn steam line 9; it is similar in construction to check valves l5and 20. 'I'he construction of these check valves is shown clearly inFig. 3, and each comprises a housing 59, removable cap plug 59a, checkball 59h, and valve seat 59e. An intake nipple 59d is adapted to beconnected to a communicating pipe connection, and a nipple 59e isadapted to be connected to an outlet pipe connection. The rise of liquidon thclower side of check ball 59h will cause it to become unseatcd andpermit the liquid to enter the outlet pipe connection. The reverse isnot,

true, however, because any pressure on thel top side of check ball 59hcould not have any unseating function. The pressure on the communicatingside of the valve is usually higher than the pressure on theoutlet side,and this, of course, aids in unseating the check lball when necessary.The presence of excess water in steam lines ,makes it difiicult tomaintain a balanced pressure throughout the heat transfer system, and itis desirable 'to employ check valves and condensation collectingchambers in order to remove water from steam lines.

I am aware that exhaust steam has been used at above atmosphericpressure for heating systems, but to my knowledge no one has evercontrolled exhaust steam for a heating system at subatmosphericpressure, and especially by means which I have provided. Among theadvantages are the ecient and economical heat and reduction of backpressure on the engine generating the exhaust steam. The initialpressure steam maybe reduced from thirty-five pounds to at leastnineteen pounds per hour per horsepower at deflnite inches of vacuum.The arrangement which I have provided entirely eliminates all thedisadvantages of the necessity of using water for condensation in thecases where exhaust steam is used for heating or process work at aboveatmospheric pressure.

The'means which I have provided are simple.

I have provided a riserand return and radiator structure ,which isconventional, and I have also valve to admit additional steam asdesired.

I have provided means for controlling the ,de`

sired amount of vacuum in the heating system to admit steam from aprimary line through a reducing valve and by my system exhaust steam maybe used as far as it will go and if there is too much of itat certaintimes a safety valve may be provided. I f the exhaust steam is notsuiiicient, steam is automatically admitted from the primary line.

In my system the diaphragm of the reducing l valve of the primary linemay also be Yplaced in multiple series with the entire load. The nearand far ends of the secondary line may be placed in series by means ofthe control or by-pass pipe to allow an equalizing of pressure betweenthe near and far ends of thesecondary line .to be registered on thecontrol or by-pass line. Thus the diaphragm in the reducing valve of theprimary line being in communication with the control or by-'pass linethe pressure on the diaphragm will vary according to the rate ofcondensation in the condensing units. When the thermostatic trap v'alveopens, bot

ends 'of the secondary line and one side of the diaphragm are placed incommunication with the vacuum pump, allowing the vacuum pump to lowerthe pressure underneath the diaphragm and throughout the` secondaryline, which allows the reducing valve to deliver more steam from theprimary line 'to the secondary line. When the heat rises in the controlline to-a set number of degrees, the thermostatic trap valve closes,cutting oi the pump from communication with the control or by-passline.Ihave provided a thermostatic trap valve for each 4. radiator so thatwhen the steam reaches the desired temperature the trap will close andit will be impossible to draw further steam through the radiator. Thevacuum pump will not only assist in exhausting air and condensationspeedily, but will assist in automatically maintaining the desiredlvacuum, as will be manifest to those skilled in the art, in view of thefollowing description.

In the modified form shown in Figs. 4 and 5, exhaust steam may be ledfrom a prime mover through an exhaust line 80 to a hot water tank 8| andoutlet pipe 82. From pipe 82 the exhaust steam may be led into anexhaust manifold 88 connected with a secondary 84, and the manifold mayalso communicate with a safety exhaust pipe 88 having a safety valve `88to furnish an outlet for excess exhaust steam. The secondary 84 leads toaradiator manifold pipe 81 and a far end pipe 88 provided with anadjustable thermostatic trap valve 89. I claim no invention in the trapitself as these traps are old and well known and adapt.

ed to close under various temperatures to prevent the passage of steam.Far end-pipe 88 leads to a condensation pipe and a pump feed pipe 1|,which in turn is adapted to feed condensation to a conventional vacuumpump 12. The vacuum pump 12 in turn is provided with a discharge pipe 13which leads to a conventional air extractor 14 on the tank 8|, andthereafter leads tothe tank 8| itself. The tank 8| is provided with ahot water discharge pipe which leads to a pump 18 adapted to pump hotwater through a hot water discharge pipe 11 leading to a steam boiler.

The radiator manifold pipe 81 is adapted to feed steam into a pluralityof radlator'branch pipes 18 and radiators 18. The radiator branch pipe18 is provided with a thermostatic trap valve 80 which may be similar tothe trap valve 89 and which will function in a similar manner. Theradiator branch pipes 18 lead to condensation pipe lines 8| which inturn lead to a return manifold line 82 which in turn is connected tocondensation pipe line 10.

Each radiator is provided with a thermostat control trap valve 83 whichmay be similar to the traps 89 and 80and function in a similar manner.The radiators communicate with condensation pipes 84 which in turncommunicate with return manifold line 82.. A by-pass pipe 85 leads fromfar end pipe 88 to the exhaust manifold 83.

A by-pass condensation pipe 88 is provided to communicate with pump feedpipe 1| and by-pass pipe 85, and is provided with an adjustablethermostatic trap valve 81, and the by-pass condensation pipe 88 is alsoprovided with a check valve 88 adapted to prevent condensation and suchfrom backing into thepipe 88 from pipe 1|.

The by-pass pipe 85 communicates at its other end with a diaphragm pipe89 which leads to the pressure compartment 90 of a diaphragm casing 9|in a live steam valve structure 92 as shown in detail in Fig. 5. In thediaphragm casing 9| there is provided a diaphragm 93 which creates notonly the steam pressure compartment 90 but also an atmospheric pressurecompartment 94. The diaphragm 93 has connected to it a vertical post 95which is operatively connected to a balance lever 98 provided withWeights 91 in a man;

ner which will be manifest to those skilled in the art.

VResting on the pcst 95 or operativelyconnected toit is a valve stem 9,8which is located in and travels in a bore |00 in the usual packing 99and the :valve structure body. The stem 98 at its upper end is enlargedas at I8| and is provided with a pair of valves |02 seating in a pair ofvalve seats |08 in the valve structure body 92. The valve structure body92 is provided with an inner chamber |88 communicating with a live steam-the same vacuum conditions throughout the system when using live steam.direct from boilers instead of exhaust steam. In the operation of mysystem the reducing valve structure 82 may be set at ten inches ofvacuum, and the vacuum pump may be set to maintain a vacuum of twelveinches. This arrangement will allow a temperature of steam in thecontrol or by-pass line 88 to be maintained at the temperature of steamat ten inches of vacuum. Whenv the thermostatic trap valve 81 starts toopen at this temperature,

'this will allow the twelve inches of vacuum in the return lines to passto the control or by-pass line and lower the pressure in the secondaryline and underneath one side of the diaphragm of the reducing valvestructure 82, causing the valves |82 to admit more steam to the systemuntil the temperature in the control line has reached the settemperature, when the thermostatic trap will be closed, cutting off thevacuum pump from the control or by-pass line 88. The thermostatic trapvalve will be balanced to maintain the degrees of heat throughout theheating system at the temperature of steam at which the reducing valveis set.

If the temperature at any individual radiator thermostatic trap valvelowers beyond the set temperature, its trap valve will open and thetwelve inches of vacuum will operate to draw the necessary steam intothe particular radiator, insuring that each radiator shall have thedesired amount of steam, regardless of its condition or distance fromthe source of steam supply.

It will be apparent that under operating conditions a drop intemperature and pressure in the control line will open trap valve 81 andthat this drop may be occasioned by a drop in the manifold 83 or in thefar end pipe 68. Also if there is sulcient drop in pipe 88, trap valve88 may be opened. Thus the control valve 92 may be opened by theactuation of either valve 89 or 81. In practice, valve 89 willordinarily be a considerable djstance away from valve 81 so that thelatter may be more sensitive to temperature changes in manifold 83 thanwill valve 89. Valve 89 will preferably be lset at the temperaturedesired to be maintained in manifold 88 and secondary 64 and valve 81will be set slightly lower. Thus if a sudden drop occurs in the systemnear secondary 64 and manifold 83, valve 81 will open and the full eectof the vacuum pump 82 will be transmitted to valve 92 and open it wideopen, if necessary, to bring up the temperature or degree of vacuum tobalance. If, however, a small drop occurs in the region of far end pipe88, valve 88 will open and unbaiance the control line 85 only an amountnecessary to unseat valve 92 and consequently admit only the requiredamount of steam to restore the system to normal.

It will be apparent that far end pipes 9 and 88 do not necessarily needto be separate pipes but may be combined with the last riser or 18. Inthese cases the control line 5,2 or 85 would be connected to the lastriser or 18 and the system would function exactly as described.

ity

By the operation of the system as described, it will be clear that theentire secondary line will be maintained at the temperature and pressurethat the control valve is set at. There will consequently be noexpansion of steam in the secondary line and risers except a negligibleamount, as the control valve is operated upon the slightest unbalancingof pressure or temperature in the control pipe; and because expansion isprevented in this manner the operation of the system will be greatlyimproved with resulting increase of'eiciency.

In installations Where the foregoing described systems are in operation,uniform savings of ten per cent. and in many instances of fifteen tothirty per cent. have been realized.

While I have illustrated and described the preferred form ofconstruction for carrying my invention into effect, this is capable ofvariation and modiiication Without departing from the spirit of ltheinvention. I, therefore, do not Wish to be limited to the precisedetails of construction set forth, but desire to avail myself of suchvariations and modifications as come within the-scope of the appendedclaims.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent is:

l. In a heat transfer system having a primary steam line, a secondarysteam line, a regulating valve interposed between said primary steamline and said secondary steam line and having a diaphragm actuated pilotvalve therefor, said pilot valve being constructed and arranged to closethe regulating valve upon an increase in pressure exerted against saiddiaphragmand return steam means, the combination of a communicating pipeconnection from near the beginning of said secondary steam line to oneside of said diaphragm, and a by-pass connection between said lastmentioned pipe connection and said return steam means arranged to allowpassage of steam from the former to the latter.

2. In a heat transfer system having a primary steam line, a secondarysteam line, a regulating valve interposed between said primary steamline and said secondary steam line and having a diaphragm actuated pilotvalve therefor, said valve being constructed and arranged to close theregulating valve upon an increase of pressure exerted .againstsaiddiaphragm, and return steam lines including the far end of saidsecondary steam line, the combination of a communicating pipe connectionfrom near ther beginning of said secondary steam line and one side ofsaid diaphragm, by-pass connections between said communicating pipeconnection and said return steam lines, and bypass connections betweensaid return Steam lines and the far end of said secondary steam line,said by-pass connections being arranged to allow passage of steam'fromthe communicating pipe connections to said'return steam lines includingthe far end of said secondary line.

3. In a heat transfer system having a plurality of radiators, asteamsupply pipe, and a return pipe therefor, the combination of a controlvalve in said supply pipe and having'a diaphragm chamber, a diaphragm insaid chamber, and means connecting said valve and said diaphragm andadapted to close said valve on an increase in the pressure in saidchamber and open said valve on a decrease in the pressure in saidchamber, a control pipe connected to said chamber and to said supplypipe, and a return pipe connection to said control pipe having athermostatic trap valve therein.

4. In a heat transfer system having a plurality of radiators, a steamsupply pipe, and a return pipe therefor, the combination of a controlvalve in said supply pipe and having a diaphragm cham' ber, a diaphragmin said chamber, and means connecting said valve and said diaphragm andadapted to close said valve on an increase in 'the pressure in saidchamber and open said valve on a decrease in the pressure in saidchamber, a oontrol pipe connected to said chamber and to said supplypipe, a return pipe connection to said control pipe having athermostatic trap valve therein, and a vacuum pump connected to saidreturnpipe.y i

5. In a heat transfer system having a plurality of radiators, a steamsupply pipe, and a return pipe therefor, the combination of a controlvalve in said supply pipe and having a diaphragm chamber, a diaphragm insaid chamber, and means connecting said valve and said diaphragm andadapted to close said valve on an increase in the pressure in saidchamber and open said valve on a decrease in the pressure in saidchamber, a control pipe connected to said chamber and to said supplypipe, a return pipe connection to said control pipe having athermostatic trap valve therein,

a vacuum pump connected to said return pipe, and a thermostatic trapvalve in said return pipe.

6. In a Yheat transfer system having a plurality of radiators, a steamsupply pipe having a far end, and a return pipe therefor, thecombination .of a control valve in said supply pipe and having adiaphragm chamber, a diaphragm in said chamber, and means connectingsaid valve and said y diaphragm and adapted to close said valve on anincrease in the pressure in said chamber and open said valve ori adecrease in the pressure in said chamber, a control pipe connected tosaid chamber and to said supply pipe, and a far end pipe connection tosaid control pipe.

7. In a heat transfer system having a plurality of radiators, a steamsupply pipe having a far end, and a return pipe therefor, thecombination of a control valve in said supply pipe and having adiaphragm chamber, a diaphragm in said chamber, and means connectingsaid valve and said diaphragm and adapted to close said valve on anincrease in the pressure in said chamber and open said valve on adecrease in the pressure in said chamber, and a control pipe connectingsaid chamber, said supply pipe, said far end pipe, and said return, saidcontrol pipe and return-connec-l tion having a thermostatic trap valvetherein.

B. In a heat transfer system having a plurality of radiators, a steamsupply pipe having a yfar end, and a return pipe therefor, thecombination of a control valve in said supply pipeland having adiaphragm chamber, a diaphragm in said chamber, and means connectingsaid valve and said diaphragm and adapted to close said valve on anincrease in the pressure in said chamber and open saidvalve on adecrease in the pressure in said chamber, a control pipe connecting saidchamber, said supply pipe, said far end pipe, and said return, saidcontrol pipe and return connection having a thermostatic trap valvetherein, a vacuum pump connected to said return, and a. thermostatictrap valve connecting said far end and said vacuum pump.

9. In a heat transfer system having a plurality of radiators, a steamsupply pipe having a far end, and a return pipe therefor, thecombination of a control valve in said supply Ipipe and having adiaphragm chamber, a ,diaphragm in said chamber, and means connectingsaid valve and said diaphragm and adapted to close said valve on anincrease in the pressure in said chamber and openv said valve on adecrease in the'pressure in said chamber, a control pipe connecting saidchamber, said supply pipe, said far end pipe, and said return. saidcontrol pipe and return connection having a thermostatic trap valvetherein, a vacuum pump connected to said return, and an adjustablethermostatic trap valve connecting said far end and said vacuum pump.

10. In a heat transfer system having a plurality of radiators, a steamsupply pipe having a far end, and a return pipe therefor, thecombination of a control valve in said supply pipe and having adiaphragm chamber, a diaphragm in said chamber, and means connectingsaid valve and said diaphragm and adapted to close said valve on anincrease in the pressure in said chamber and open said valve on a thepressure in said chamber, a control pipe connecting said chamber, saidsupply pipe, said far end pipe, and said return, a vacuum pump connectedto said return, a thermostatic trap valve connecting s'aid far end andsaid vacuum pump, and a by-pass connection between said control pipe andsaid vacuum pump having a thermostatic trap valve therein.

l1. In a heat transfer system having a plurality of radiators. a primarysupply pipe therefor, a secondary supplypipe therefor having a far endand a return for said radiators, the combination of a control valvehaving a diaphragm chamber, a diaphragm in said chamber, and meansconnecting said valve and said diaphragm and adapted to close said valveon an increase in the pressure in said chamber and open said valve on adecrease in the pressure in said chamber, and means to prevent expansionof steam insaid secondary, comprising a control pipe connecting saiddiaphragm chamber, said secondary supply, and said return, said controlpipe and return connection having aA thermostatic trap valve therein.

12. In a heat transfer system having a plurality of radiators, a primarysupply pipe therefor, a secondary supply pipe .therefor having a far endand a return for said radiators, the combination of a control valvehaving a diaphragm chamber, a diaphragm in said chamber, and meansconnecting said valve and said diaphragm and adapted to close said valveon an increase in the pressure in said chamber and open said valve on adecrease in the pressure in said chamber, and means to prevent expansionof steam in said secondary, comprising a control pipe connecting saiddiaphragm chamber, said secondary supply, and said far end.

13. In a heat transfer system having a plurality of radiators, a primarysupply pipe therefor, a secondary supply pipe therefor havingV a far endand a return for said radiators, the combination of a control valvehaving a diaphragm chamber, a diaphragm in said chamber, and meansconnecting said valve and 'said diaphragm and adapted to close saidvalve on an increase in the pressure in said chamber and open said valveon a decrease in the pressure in said chamber, and means to preventexpansion of steam in said secondary, comprising a control pipeconnecting said diaphragm chamber, said secondary supply, said far end,and said return, said control pipe and return connection having athermostatic trap valve therein.

14. In a heat transfer system having a conventional radiator systemprovided with a redecrease in turn pipe, a primary live steam supplypipe, a secondary exhaust steam supply pipe, means to admit exhauststeam to said system, means to4 admit live steam to said system, saidlive steam admitting means comprising a reducing and control valve forcontrolling said live steam admitting means, 'said valve having adiaphragm chamber, a diaphragm inr said chamber, and means connectingsaid valve and said diaphragm and adapted to vclose said valve on anincrease in the pressure therein and open said .valve on a decrease inthe pressure therein, a vacuum pump connected to said return pipe, and acontrol pipe connecting said diaphragm chamber, said secondary exhauststeam supply pipe, and said return pipe, andhaving a thermostatic trapvalve in said control line connection to said return pipe. t

15. In a heat transfer system having a plurality of radiators, a primarysupply pipe therefor, a secondary supply pipe therefor having a far endand a return for said radiators, means to prevent expansion of steam insaid secondary supply pipe, said means including a control valve betweensaid supply pipes and a control pipe for said valve connected to saidsecondary pipe and said far end and said return, said means including avalved aperture between said primary and secondary supply pipes, saidaperture adapted to be varied inversely in proportion to the averagepressure in said secondary supply pipe.

16. In a heat transfer system having a plurality of radiators, a primarysupply pipe therefor, a secondary supply pipe therefor having a far endand a return for said radiators, means to prevent expansion of steam insaid secondary supply pipe and risers, said means including a controlvalve between said supply pipes and a control pipe for said valveconnected to said secondary pipe and said far end and said return, saidmeans including a valved aperture between said primary and secondarysupply pipes, said aperture adapted to be varied inversely in proportionto the average pressure in said secondary supply pipe and risers.

1'7. In a heat Vtransfer system having a plurality of radiators, aprimary supply pipe there- `for, a secondary supply pipe therefor havinga far end and a return for said radiators, means to maintain uniformsteam pressure in said secondary including said far end, said meansincluding a control valve between said supply 'pipes and a control pipefor said valve connected to said secondarypipe and said far end and saidreturn, said means including a valved aperture between said primary andsecondary supply pipes,`said aperture adapted to be varied inversely inproportion to the average pressure in said secondary supply pipeincluding said far end.

18. In a heat transfer system having a plurality of radiators, a primarysupply pipe therefor, a secondary supply pipe therefor having a far endand a return for said radiators. means to maintain uniform steampressure in said'secondary including said far end and risers, said meansincluding a control valve between said supply pipes and a con'trol pipefor said valve conrality of radiators, a primary-supply pipe therefor, asecondary supply pipe therefor having a far end and a return for saidradiators, means to maintain .uniform temperature vand pressure in saidsecondary and risers, said means includ-l ing a control valve `betweensaid supply pipes and a `control pipe for said valve connectedto saidsecondary pipe and said far end and said return, said means including avalved aperture between said primary and secondary supply pipes, saidaperture adapted to be`varied inversely in proportion to theaveragepressure in said secondary .supply pipe and risers.

20. In a heat transfer system having a primary steam line and asecondary steam line having a far end, a. regulating valve interposedbetween said primary and secondary lines, diaphragm actuated controlmeans for said regulating valve, said control means adapted to close theregulating valve upon increase in pressure exerted against saiddiaphragm and open said valve upon a decrease in pressure exertedagainst said diaphragm, and means adapted to subject said control meanstothe average pressure in said secondary steam line including said farend.

21. In a heat transfer system having a primary steam line and asecondary steam line having a far end, a regulating valve interposedbetween said primary and secondary lines, diaphragm actuated controlmeans for said regulating valve, said control means adapted to close theregulating valve upon increase in pressure exerted against saiddiaphragm and open said valve upon a decrease in pressure exertedagainst said diaphragm, and means adapted to subject said control meansto the average pressure in said secondary steam line.

22. In a heat transfer system having a primary steam line and asecondary steam line having a far end, a regulating valve interposedbetween said primary and secondary lines, pressure actuated controlmeans for said regulating valve, said control means adapted to close theregulating valve upon increase in pressure and open said valve upon adecrease in pressure, and means adapted to subject said control means tothe average pressure in said secondary steam line including said farend. v

23. In a heat transfer system having a primary steam line and asecondary steam line having a far end, a regulating valve interposedbetween said primary and secondary lines, pressure actuated controlmeans for said regulating valve,

said control meansadapted to close the regulating valve upon increaseinl pressure and open said valve upon a decrease in pressure, and meansadapted to subject said control means to the average pressure in saidsecondary steam line.

24. In a heat transfer system having a primary steam line and asecondary steam line having a far end, a regulating valve interposedbetween said primary and secondary lines, pressure actuated controlmeans for said regulating valve, said control means adapted to close theregulating valve upon increase in pressure and open said valve upon adecrease in pressure, and means adapted to subject said control means tothe instantaneous average pressure in said secondary steam line. v

25. In a heat transfer system having a primary steam line and asecondary steam line,a regu-.- lating valve interposed `between saidprimary and secondary lines, pressure actuated control means for saidregulating valve, said control means adapted to maintain said regulatingvalve partially open,`said open degree being determined by the averagepressure in said secondary steam line.

26. In a heat transfer system having a primary steam line and asecondary steam line, a regulating valve interposed between said primaryand secondary lines, pressure actuated control means for said regulatingvalve, said control means Iincluding balanced actuating means, the pointof balance thereof being determined by the average pressure in saidsecondary steamline.

27. In a heating system having a primary steann line and a secondarysteam line including afar end, and a return, means to control theadmission of steam from said primary to said secondary, said meansincluding an automatically actuatable valve, the actuating means or saidvalve including a member responsive to changes in the average pressurein said secondary, said far end and said return.

28. In a heat transfer system having a plurality of radiators, a primarysupply pipe therefor, a secondary supply pipe therefor, having a nearend and a far end, a pressure actuated control valve between saidprimary and secondary supply pipes,

and an equalizing pressure control pipe connecting said valve actuatorwith the said near end and far end of said secondary supply pipe.

29. In a heat transfer system having a plurality of radiators, a primarysupply pipe therefor, a secondarysupply pipe therefor, having a near endand a far end, a return and vacuum means -for said return, a pressureactuated control valve nection.

' SAMUEL P.

